Criss Cross
How to do it: Lie on your back and bring your knees in toward your chest. Lift your shoulders off the floor and clasp your hands behind your head. Exhale and squeeze your bellybutton toward the floor. Inhale. As you exhale, extend your left leg as you twist your torso and reach your left elbow to your right knee. Inhale as you begin to switch to the other side. Exhale as you extend the right leg, tighten the core and reach that right elbow. Continue to alternate in this way. Complete 3 sets of 10-20 reps.
Pro tips: Make sure you’re not hunching those shoulders up toward your ears. Relax them down. Keep the focus of the rotation in the abs. Don’t lead with the elbows (i.e. rotate that elbow toward your face); you’ll lose the engagement in the core that way.
Pendulum
How to do it: Lie with your back on the floor. Lift your knees up to 90 degrees and point your toes. Inhale and suck your navel into your spine. Exhale as you rotate your knees slightly to the right. Maintain core engagement. Then rotate your knees to the left. Perform 10-20 reps total for 3 sets.
Pro tip: To fire up that core, think about gluing your lower back to the floor.